A modified OMP method for multi-orbit three dimensional ISAR imaging of the space target

The conventional two dimensional(2D)inverse synthetic aperture radar(ISAR)imaging fails to provide the targets'three dimensional(3D)information.In this paper,a 3D ISAR imaging method for the space target is proposed based on mutliorbit observation data and an improved orthogonal matching pursuit(OMP)algorithm.Firstly,the 3D scattered field data is converted into a set of 2D matrix by stacking slices of the 3D data along the elevation direction dimension.Then,an improved OMP algorithm is applied to recover the space target's amplitude information via the 2D matrix data.Finally,scattering centers can be reconstructed with specific three dimensional locations.Numerical simulations are provided to demonstrate the effectiveness and superiority of the proposed 3D imaging method.

Contour reconstruction of three-dimensional spiral CT damage image

In order to improve the diagnosis and analysis ability of 3D spiral CT and to reconstruct the contour of 3D spiral CT damage image,a contour reconstruction method based on sharpening template enhancement for 3D spiral CT damage image is proposed.This method uses the active contour LasSO model to extract the contour feature of the 3D spiral CT damage image and enhances the information by sharpening the template en.hancement technique and makes the noise separation of the 3D spiral CT damage image.The spiral CT image was procesed with ENT,and the statistical shape model of 3D spiral CT damage image was established.The.gradient algorithm is used to decompose the feature to realize the analysis and reconstruction of the contour feature of the 3D spiral CT damage image,so as to improve the adaptive feature matching ability and the ability to locate the abnormal feature points.The simulation results show that in the 3D spiral CT damage image contour reconstruction,the proposed method performs well in the feature matching of the output pixels,shortens the contour reconstruction time by 20/ms,and provides a strong ability to express the image information.The normalized reconstruction error of CES is 30%,which improves the recognition ability of 3D spiral CT damage image,and increases the signal-to noise ratio of peak output by 40 dB over other methods.

Application of Opening and Closing Morphology in Deep Learning-Based Brain Image Registration

In order to improve the registration accuracy of brain magnetic resonance images(MRI),some deep learning registration methods use segmentation images for training model.How-ever,the segmentation values are constant for each label,which leads to the gradient variation con-centrating on the boundary.Thus,the dense deformation field(DDF)is gathered on the boundary and there even appears folding phenomenon.In order to fully leverage the label information,the morphological opening and closing information maps are introduced to enlarge the non-zero gradi-ent regions and improve the accuracy of DDF estimation.The opening information maps supervise the registration model to focus on smaller,narrow brain regions.The closing information maps supervise the registration model to pay more attention to the complex boundary region.Then,opening and closing morphology networks(OC_Net)are designed to automatically generate open-ing and closing information maps to realize the end-to-end training process.Finally,a new registra-tion architecture,VM_(seg+oc),is proposed by combining OC_Net and VoxelMorph.Experimental results show that the registration accuracy of VM_(seg+oc) is significantly improved on LPBA40 and OASIS1 datasets.Especially,VM_(seg+oc) can well improve registration accuracy in smaller brain regions and narrow regions.

Bi-prism-based single-lens three dimensional digital image correlation system with a long working distance: Methodology and application in extreme high temperature deformation test

As a novel three dimensional digital image correlation(3 D DIC) method, the bi-prism-based single lens(BSL) 3 D DIC method has been proposed and developed in recent years. Making use of a bi-prism, this method is able to perform a 3 D DIC measurement using only a single camera. Thus, the integration level of a BSL 3 D DIC system could be much higher than that of the double-camera3 D DIC system. In this paper, using a small-angle bi-prism and a camera with a longer focal length, a special BSL 3 D DIC system with a long working distance is designed for measurements in extreme environments. The principle of the system is first studied,and practical methods are then proposed for the system set-up and the determination of system parameters. Then, feasibility of the measurement system is verified by out-of-plane rigid-body translation tests. Finally, the BSL 3 D DIC system is proven to be capable of combining with a high-temperature testing instrument to perform deformation tests in a high-temperature environment of up to 1500°C.

Preoperative surgical planning and simulation of complex cranial base tumors in virtual reality

The extremely complex anatomic relationships among bone, tumor, blood vessels and cranial nervesremains a big challenge for cranial base tumor surgery. Therefore, a good understanding of the patient specific anatomy and a preoperative planning are helpful and crucial for the neurosurgeons. Three dimensional （3-D） visualization of various imaging techniques have been widely explored to enhance the comprehension of volumetric data for surgical planning.